After Yelp walked away from a $500M offer from Google, Yelp reviews which were a prime source of reviews placed on Google’s local business listings (Now called Google Places), were removed. Yelp reviews were still indexed by Google and would come up on searches, but were not integrated into a individual business Google Place. Since then I have been recommending not focusing on asking customers to review on Yelp as they were not being included on Google Places.
It seems that in the past few weeks, Google is again integrating Yelp reviews into Google places. Not only that, but Yelp reviews are the first reviews Google lists for businesses that have Yelp reviews (indicated by www.yelp.com/biz/name of business ). Yelp reviews are before reviews placed on Google (indicated by maps.google.com) or any other review service such as Citysearch, or yellowpages.
So if you have been getting good reviews rejoice. If Yelp has not been your friend, start pointing your happy customers to review your business on Yelp